1. Field of the Invention
This invention relates to quinone-coupled polyphenylene oxides having an average hydroxyl group per molecule value greater than the average hydroxyl group value associated with polyphenylene oxide reactants employed in the reaction with quinones.
2. Description of the Prior Art
Self-condensation reactions of certain phenols employing oxygen in combination with an effective oxidative coupling catalyst system to form prior art polyphenylene oxides, i.e., polyphenylene oxides having an average hydroxyl group per molecule of 1.0 or less, are described in various U.S. patent applications including Hay's U.S. Pat. Nos. 3,306,879; 3,914,266; application Ser. No. 540,473, filed Jan. 13, 1975, now U.S. Pat. No. 4,028,341 a continuation-in-part of Ser. No. 441,295, filed Feb. 11, 1974, now abandoned; and Olander's U.S. Pat. Nos. 3,956,442; 3,965,069; 3,972,851; and Ser. No. 582,910, filed June 2, 1975, now U.S. Pat. No. 4,054,553. All of the Hay and Olander disclosures referenced above are incorporated herein in their entirety by reference.
Cooper's U.S. Pat. No. 3,496,236 discloses the equilibration of polyphenylene oxide and certain phenols in the presence of phenoxy radical carried out under oxidizing reacting conditions. My U.S. Pat. No. 3,367,978 discloses the preparation of novel compositions of matter resulting from the reaction of a phenol and a polyphenylene oxide under equilibration reaction conditions, i.e., carried out under oxidizing reaction conditions. All of the Cooper and my disclosures referenced above are incorporated herein in their entirety by reference.
Heretofore, quinone reaction product species known to be most deleterious to the color of polyphenylene oxides have been separated therefrom by precipitating the polymer from a solvent system in which the quinone species are soluble. Heretofore, multiple solvent precipitation and/or extraction techniques have been employed to remove significant amounts of quinone, e.g., up to one percent of quinone based on the weight of polymers, prior to isolation of prior art polyphenylene oxides as a solid reaction product suited to further processing to form a suitable commercial end product.
Unexpectedly and advantageously I have found that quinones can be reacted with polyphenylene oxides to form novel quinone-coupled polyphenylene oxides having an average hydroxyl group value greater than the hydroxyl group value associated with the polyphenylene oxide reactants. The resulting quinone-coupled polyphenylene oxides are new compositions of matter substantially free of quinone color entities, which are suited to the manufacture of thermoplastic compositions having improved chemical and physical properties.